<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <link rel="stylesheet" href="./reset.css" />
    <title>Document</title>
    <style>
      #footer {
        background-color: burlywood;
        clear: both;
      }
      #header {
        background-color: chocolate;
      }
      div {
        text-align: center;
        font-size: 18px;
        line-height: 18px;
      }
      .main {
        overflow: hidden;
        padding-left: 300px;
        padding-right: 200px;
      }
      .center {
        background-color: crimson;
        width: 100%;
        float: left;
      }
      .left {
        width: 300px;
        background-color: blue;
        float: left;
        margin-left: -100%;
        position: relative;
        left: -300px;
      }
      .right {
        width: 200px;
        background-color: blueviolet;
        float: left;
        margin-right: -200px;
      }
    </style>
  </head>
  <body>
    <div id="header">
      <h5>header</h5>
    </div>
    <div class="main">
      <div class="center">center</div>
      <div class="left">left</div>
      <div class="right">right</div>
    </div>
    <div id="footer">
      <h5>footer</h5>
    </div>
  </body>
</html>
